Nov. 15, 1924 
Reaction Between Formaldehyde and Proteins 
479 
Table YIII .—The changes in the titrable acidity and Ph values of formolized 
horse-blood serum 
Grams of formeldehyde added per 100 
c. c. of serum 
Time of contact 
0.74 
1.85 
Ph 
Acidity® 
Ph 
Acidity® 
Before treatment... _ __ ... _ .. _ 
6.6 I 
8.0 
6.6 
8.0 
3 minutes . . . _____ 
6.1 
5.9 
1 hour . __ . _ _ .. 
6.1 
36.0 
5.9 
38.0 
6 hours__ .. _ __ _ 
6.1 
28.0 
5.8 
30.0 
24 hours _ _ _ __ .. .. _ ___ 
6.1 
15.0 
5.6 
18.0 
72 hours .. . . _ 
6.0 
15.0 
5.6 
15.0 
° C. c. N/10 NaOH required to neutralize 100 c. c. of serum. 
In this experiment the Ph value 
of the serum decreased and the titrable 
acidity increased on the addition of 
formaldehyde to the serum, and the 
changes in each were greater in extent 
when greater amounts of formaldehyde 
were added. However, while the im¬ 
mediate increase in titrable acidity 
was followed by a decline, no converse 
change occurred in the P H value, which 
tended to decrease throughout the dura¬ 
tion of the experiment. Attention is 
called to the fact that the serums re¬ 
ported in these two tables had different 
Ph values. The only explanation that 
can be offered is that the two serums 
were different, that they were derived 
from different species of animals, and 
that the serum with the lower P H value 
had been kept longer before the experi¬ 
ment was begun. From the results of 
Experiments V and VI it is apparent 
that the addition of formaldehyde to a 
serum results in a decrease of the Ph 
value of the serum. It is also indicated 
that the change in P H value of serums 
after formolization is not the sole factor 
controlling or inducing the transforma¬ 
tion of the more soluble proteins into 
euglobulins. 
MISCELLANEOUS OBSERVATIONS 
In addition to the observations re¬ 
corded in the preceding sections of this 
paper, a number of other observations 
regarding the behavior of the protein, 
including the factors influencing that 
behavior, have been made. It is not 
believed that the later observations 
have been substantiated sufficiently to 
warrant their presentation in detail.' 
However, a few of these observations 
will be discussed briefly because they are 
considered of interest and importance. 
Sclrwarz {15) found that when formal¬ 
dehyde was added to serum a part of 
the aldehyde immediately, while an¬ 
other part gradually, combined. Similar 
results have attended experiments 
with formolized serums made in the 
hope of gaining information regarding, 
first, the relation between the rate of 
disappearance of uncombined forn^al¬ 
dehyde and the rate of production of 
euglobulins, and, secondly, the rela¬ 
tions between the amount of formal¬ 
dehyde added and the amount com¬ 
bined. Thus, in several experiments 
1.85 per cent of formaldehyde was 
added to serums. Following the addi¬ 
tion of the aldehyde, the serums were 
examined at intervals for the purpose 
of determining the proportion of free 
formaldehyde which had disappeared 
from solution. In every test conducted 
in this way it was found that (a) a small 
amount, usually less than 0.33 per 
cent, disappeared, probably combined, 
within the first few minutes of the test, 
and (6) no increase in this amount 
occurred within the first five or six 
hours of the experiment. When the 
amount of aldehyde found to have 
disappeared in the first few minutes of 
the test was small, i. e., less than 0.20 
per cent, and when the examination 
was repeated at the end of 24 hours, 
there was in some cases an indication 
that a slight additional amount of free 
formaldehyde had disappeared. 
In regard to a relation between the 
amount of formaldehyde added to the 
amount combined: In a series of 12 
1339—25t-2 
